Troubleshooting 4-Way Harness that Shorted Out on 2009 Ford F-350

Question:

I accedently shorted out the four way plug. I saw small sparks and realized I had grounded out the plug. I have looked at the fuses I thought I might have blown but still can’t find the problem. I have no power to any wires leading to the plugs .

asked by: Tom

Helpful Expert Reply:

What I recommend doing is testing the pins on the factory US connector (not the 4-Way/7-Way connector, but the OEM port that the harness is plugged into) on your truck or the wires leading up to it with a circuit tester like # PTW2993. If you get power at this plug, then you will just need to replace the harness with a new 7-Way like the Curt # C55774 and this should resolve the issue.

If you do not get power on the factory plug, then the issue is somewhere on your factory wiring or you have a blown fuse (which you seemed to have already checked). If this is the case, then you will simply need to inspect the truck's wiring starting at the connector. You can use the circuit tester to test the wires at various locations as you run up the truck to see if you can find where the power stops.

expert reply by: Chris R